Transcript Document

REFINERIES
GROUP 6:
Blázquez Díaz, Mª Luisa
Chasco Aristimuño, Javier Eloy
Espejo Gonzalez, Pablo
Pereda Mateo, Ignacio
INTRODUCTION
Petroleum refineries are complex plants, where the
combination and sequence of processes is usually very
specific to the characteristics of the raw materials (crude oil)
and the products to be produced.
The European Refinery industry:
The mineral oil and gas refinery industry is an important and strategic
industry. Mineral oil refineries alone provide 42% of EU energy
requirements and 95% of the fuels required for transport.
About 100 mineral oil refineries have been identified in EU, Switzerland
and Norway and together they process around 700 million tonnes per
year.
Estimations show that the mineral oil refinery sector has 55000 direct
employees and some 35000 indirect employees.
INTRODUCTION
This figure shows only the
main pollutants generated
by refineries, but more than
90 specific compounds have
been identified. The great
majority are pollutants to air.
RAW MATERIAL AND ENERGY
CONSUMPTION
Heat and electricity are needed to run a refinery. The
fairly extensive heat requirement is generally satisfied
by fuel combustion. Electricity can be generated in the
refinery and it can be bought from the grid.
Normally, most or all of the gaseous and liquid
refinery fuels used are by-products of refinery
processes. The composition and quality of these fuels
vary with the crude oils processed.
RAW MATERIAL CONSUMPTION
Water and steam are used in the various refinery processes to
assist the distillation process or the cracking of hydrocarbons and
in scrubbing, quenching or (steam) stripping.
Petroleum refineries use relatively large volumes of water: in the
processes; in steam generation and, especially, in cooling
systems.
The principal raw material input to petroleum refineries is crude
oil
Coke is burnt in the catalytic cracking regenerator and coking
process and represents a heat production source in the refinery.
Coal, as imported fuel, is not applied in European refineries.
Refinery fuel gas (RFG)
The majority of the fuel used in a refinery is gas (methane,
ethane and ethylene in combination with excess hydrogen).
RAW MATERIAL CONSUMPTION
 THE MAIN OPERATIONS: PURPOSE AND
PRINCIPLE & FEED AND PRODUCT
STREAMS:
1. Alkylation:
The purpose of alkylation is to yield high-quality motor fuel
blending
Low-molecular weight olefins (C3-C5) and isobutane are
used as alkylation unit feedstocks.
RAW MATERIAL CONSUMPTION
2. Base oil production:
Although only 20 % of EU+ refineries produce base oil.
The feedstocks to a conventional base oil complex are
waxy distillate side-streams from vacuum distillation
units and the extract from deasphalting units.
3. Catalytic cracking:
Catalytic cracking is the most widely used conversion
process for upgrading heavier hydrocarbons into more
valuable lower boiling hydrocarbons.
Normally the main feed stream to a catalytic cracking
unit (catcracker) is the heavy vacuum distillate stream
from the vacuum distillation unit.
RAW MATERIAL CONSUMPTION
4. Catalytic reforming:
So the purpose of a catalytic reformer is to upgrade these streams
for use as a gasoline blendstock.
The typical feedstocks to catalytic reformer units are the
hydrotreated straight-run heavy naphtha stream from the crude
distillation unit and, if applicable, the hydrotreated heavy naphtha
stream from the hydrocracker unit and medium catcracked naphtha
stream.
5. Coking processes:
Coking is a severe thermal cracking process used primarily to
reduce refinery production of low-value residual fuel oils and
transform it into transportation fuels, such as gasoline and diesel.
As the coking process is a thermal destruction process, the quality
of the feed in terms of metal content, Concarbon number and other
contaminants is not critical. As a matter of fact, coking is
predominantly used when the feed has a high Concarbon number
and contains high quantities of impurities which cannot be handled
in catalytic conversion processes.
ENERGY CONSUMPTION
The capacity of the combustion plants in a refinery
varies widely from less than 10 to up to 200
megawatts thermal input (MWth), and the total
installed capacity ranges from several hundred to
more than 1500 MWhth in the largest refineries.
EMISSIONS
 Emissions to the atmosphere:
Typically, more than 60 % of
refinery air emissions are related
to the production of energy for
the various processes.
The main air emissions from
a refinery are CO2, SOx, NOx,
VOC and particulates (dust, soot
and associated heavy metals
(mainly V and Ni)).
EMISSIONS
EMISSIONS
 Particulate emissions:
The concern with particulate emissions stems from health
effects.
The main emission sources are process furnaces/ boilers,
catalytic cracker regenerators, coke plants, incinerators,
decoking & sootblowing of furnaces and the flare.
The range of emissions found in European refineries is from
100 to 20000 tonnes of particulates emitted per year.
EMISSIONS
 Emissions to water:
The main water contaminants are
hydrocarbons, sulphides, ammonia and some
metals
EMISSIONS
 Soil and groundwater contamination:
The main sources of contamination of soil and
groundwater by oil are typically those places along
the handling and processing train of crude to
products where hydrocarbons can be lost to the
ground. These are commonly associated with the
storage, transfer, and transport of the hydrocarbons
themselves or of hydrocarbon-containing water. The
possibility of contamination by other substances
such as contaminated water, catalysts and wastes
also exists.
BEST AVAILABLE TECHNIQUES (BAT)
BAT assessment :
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Environmental performance is the main criterion used to
determine BAT. Moreover, a technique considered to be BAT
should have a demonstrated applicability within the refinery
sector or in another industrial sector.
A technique considered to be BAT needs to be economically
viable within the sector. , it is considered economically
viable within the refinery sector if it
has already been applied on a certain number of occasions
within the refinery sector or other similar industrial sectors.
Operational data and applicability are criteria considered as
limitations for the implementation of BAT in certain
circumstances General applicability problems
in the implementation of techniques in existing installations
are, for example, space, operational problems…
Generic (whole refinery)
BAT
What is a BAT?
They are techniques for continuous improvement of
environmental performance. They provide the framework
for ensuring the identification, adoption of and adherence to
BAT options that, whilst often down-to-earth, are
important. These good housekeeping/management
techniques/tools often prevent emissions.
Purposes of BAT
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Implement and adhere to an Environmental Management System
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Improve stability of unit operation by applying advanced process control and limiting
plant upsets, thereby minimising times with elevated emissions (e.g. shutdowns and startups)
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Apply good practices for maintenance and cleaning
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Implement environmental awareness and include it in training programmes
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Implement a monitoring system that allows adequate processing and emission control.
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Improve the energy efficiency (reduction of all air pollutants generated by combustion) by
enhancing heat integration and recovery throughout the refinery, applying energy conservation
techniques and optimising the energy production/consumption.
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Reduce sulphur dioxide emissions.
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Reduce nitrogen oxides emissions.
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Reduce particulate emission
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Reduce volatile organic carbons emissions
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Reduce discharges to water
BAT for reduce sulphur dioxide
emissions
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Quantifying the sulphur emissions from various refinery
sources to identify the main emitters in each specific
case.
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Using BAT applicable to SO2 emission reduction in the
energy system, catcrackers and cokers
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Reducing SO2 emissions from typically small contributors
BAT for reduce nitrogen oxides
emissions
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Quantifying the NOx emission sources in order to identify
the main emitters (e.g. furnaces and boilers, the FCC
regenerators and gas turbines) in each specific case
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Using BAT applicable to NOx reduction in the energy
system and catcracker
BAT for reduce particulate emission
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Quantifying the particulate emission sources (especially
furnaces and boilers, the FCC regenerators and cokers) in
order to identify the main emitters in each specific case.
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Minimising the particulate emissions from solids handling
situations (catalyst loading/unloading, coke handling,
sludge transport) by applying good housekeeping and
control techniques.
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Using BAT applicable to particulate reduction in the
energy system, catcrackers and cokers
BAT for reduce volatile organic
carbons emissions
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Quantifying VOC emission sources in order to identify the main emitters in each specific case
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Using a maintenance drain-out system
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Selecting and using low-leakage valves such as graphite-packed valves or equivalent (especially important
for control valves) for lines containing product with a high vapour pressure.
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Using low leak pumps (e.g. seal-less designs, double seals, with gas seals or good mechanical seals) on
product lines carrying fluid with a high vapour pressure
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Minimising flanges (easier to apply in the design stage), installing sealing rings on leaking flanges
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Blinding, plugging or capping open-ended vent and drain valves
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Routing relief valves with high potential VOC emissions to flare
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Routing compressor vents with high potential for VOC emissions back to process and when not possible
(e.g. vent compressor distance pieces) to refinery flare for destruction
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Using totally closed loop in all routine samplers that potentially may generate VOC emissions
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Minimising flaring
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Using BAT applicable to VOC reduction in storage and handling
BAT for reduce discharges to
water
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apply a water management scheme (as part of the EMS)
aimed at reducing:
a) the volume of water used in the refinery by:
- water stream integration options including water optimisation studies
-re-using as much as possible the cleaned waste water
-applying techniques to reduce waste water generated within each
specific process/activity
b) the contamination of water by:
- segregation of contaminated, low-contaminated or non-contaminated
water
streams and, where possible, drainage systems
-segregation of “once-through” cooling water from process effluent until
after
this has been treated
-good housekeeping in operation and maintenance of existing facilities
-spill prevention and control
-applying techniques to reduce contamination of waste water within each
specific process/activity
EMERGING TECHNIQUES
This chapter contains those techniques
that may appear in the near future and that
may be applicable to the refinery sector.
Throughout its history the refining industry has
continuously developed new and improved
processes in response to changes in feed quality,
product specifications, product slates, new
product outlets and economic and environmental
requirements but These developments have
slowed down in recent years for three reasons:
EMERGING TECHNIQUES
1.
Large oil companies are cutting down on their R&D budgets,
and are more and more relying on third parties for new
developments in refinery technology and catalytic processes.
2.
Technological developments are concentrating on optimising
current systems for higher yields, higher energy efficiency
and shorter downtimes rather than novel processes.
3.
The current tool box of conversion, separation, treatment
and environmental technologies seems adequate and
sufficient to meet any desired product slate and product
specifications for the coming decade as well as meeting
stringent regulatory requirements;
EMERGING TECHNIQUES
 Alkylation:
Numerous companies are putting a large R&D effort into the development of a
new solid catalyst for the alkylation process.
Technology providers claim that these techniques will be ready in the
market in one to two years.
EMERGING TECHNIQUES
 Base oil production:
A recently published new technology is the application of
membranes for solvent recovery in the solvent
extraction/dewaxing processes. Driving force is the
reduction in energy consumption.
 Energy system:
The search for further energy improvements is
continuing, with the current focus on attractive
cogeneration opportunities and more complex heat
integration.
EMERGING TECHNIQUES
 Catalytic cracking:
Some promising lines of investigation for the improvement of
the environmental performance of catcrackers are:
1.
2.
3.
4.
the capability to process heavier feedstocks, containing more
contaminants such as vanadium and nickel and having a higher
Conradson Carbon Residue (CCR) content. Responses that are being
developed are: continue the development of more active catalysts
and more effective catalyst regeneration. Driving forces are the
reduction of residue and higher overall refinery efficiency.
hot ceramic filters can be retrofitted to the underflow of third stage
cyclones.
improvement of the catalyst separation by use of a magnet (Kellogg
Tech company)
other flue gas desulphurization includes CanSolv’s amine scrubbing
system for SO2 removal.
EMERGING TECHNIQUES
 Hydrogen production:
Some promising lines of investigation in hydrogen
production technologies are:
1.
the hydrocarb process, in which the residual oil is
essentially cracked to carbon and hydrogen. It has
been calculated in a refinery of 4.98 t/yr that this
process can increase by 40 % the total gasoline
production.
2.
methane pyrolysis, which takes advantage of the
thermal decomposition of natural gas and the direct
production of hydrogen while sequestering the carbon
or using the carbon for other commodity purposes.
Consequently the CO2 generation is completely
eliminated
EMERGING TECHNIQUES
 Hydrogen-consuming processes:
Some promising lines of investigation for the
improvement of the environmental performance of
energy systems are:
1.
residue hydrotreating and hydroconversion
processes (e.g. slurry bed technology). This process
has only been demonstrated at semi-commercial scale
and no commercial plants are in operation yet.
2.
gasoline deep desulphurization techniques with a
lower hydrogen consumption are currently under
development. Parameters are not yet available.
EMERGING TECHNIQUES
 Integrated refinery management:
1.
Leak detection technology:
Smart LDAR. This device is able to detect (using
laser technology) fugitive hydrocarbon emissions by
real time video imaging of the equipment under
surveillance. It allows the user to identify at a
refinery the zones in which the greatest emissions
are located so that an LDAR using sniffing techniques
can focus on the high emission items.
This technology is under development and a number
of technical issues need resolving before it is ready
for use as a routine tool.
EMERGING TECHNIQUES
 Integrated refinery management:
2. Waste gas treatments
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Some developments to be mentioned are:
sulphur dioxide removal by SO2 capture from
flue gas and conversion into liquid sulphur.
biological H2S removal
particulate abatement techniques by new
developments including ceramic filters and a
rotating particulate separator
CO2 abatement techniques.
REFINERIES
GROUP 6:
Blázquez Díaz, Mª Luisa
Chasco Aristimuño, Javier Eloy
Espejo Gonzalez, Pablo
Pereda Mateo, Ignacio